What Internxt does well
Internxt is, in most respects, exactly the kind of product this site argues for. It is based in Valencia, Spain, operates under GDPR, and stores files across European data centres. Its architecture is zero-knowledge with AES-256: files are encrypted on your device before upload, and Internxt cannot read them. Its client apps — desktop, web, mobile and CLI — are open source, with most major repositories published under AGPL-3.0. And it has already gone further than many: Internxt has had its web, mobile and desktop apps and cloud services penetration-tested by Securitum, a European security firm.
It has also adopted post-quantum cryptography: Internxt states it has implemented Kyber-512, the parameter set NIST standardized as ML-KEM-512.
So this is not the usual "incumbent that gets the architecture wrong." Internxt gets most of it right. The honest comparison below is narrow, and we will keep it that way.
Why people look for an alternative
Because Internxt and ShieldFive agree on so much — EU hosting, open source, zero-knowledge AES-256, and post-quantum encryption in principle — the reasons to compare them are specific:
- A higher post-quantum security category. They want the largest standardized post-quantum margin, not the smallest, for files with a long confidentiality lifetime.
- More free space. They want a larger free quota to evaluate the product properly, or to keep.
These are differences of degree, not of architecture. If neither matters to you, Internxt is a genuinely good answer and you should treat it as one.
Where ShieldFive differs
ShieldFive and Internxt share more than they differ on. Both are EU-based, both are open source, and both are zero-knowledge with AES-256 by default. The real differences are these.
A higher post-quantum security category. Both products ship post-quantum key encapsulation, so this is not "post-quantum versus not." It is which parameter set. Internxt describes its post-quantum layer as Kyber-512, which NIST standardized as ML-KEM-512 — security category 1, the lowest of the three standardized levels, with a target roughly equivalent to AES-128. ShieldFive defaults every new upload to ML-KEM-1024 (FIPS 203), security category 5, the highest level the standard defines, combined with a classical cipher in a hybrid suite so that a break in either component alone does not expose the file. Category 1 is a real post-quantum guarantee; ShieldFive simply targets the largest margin available, on every upload by default.
This matters most under "harvest now, decrypt later" — an adversary copying ciphertext today to decrypt once a quantum computer exists. For data with a long confidentiality lifetime, the size of the post-quantum margin is the variable you are choosing, and ShieldFive chooses the maximum.
A larger free tier. Internxt's pricing page lists a free tier of 1 GB for life. ShieldFive's free tier is 20 GB with no card. If you want room to actually evaluate the workflow — or to keep a meaningful amount of data on the free plan — that is a concrete, checkable difference.
No AI training and no scanning. Because both Internxt and ShieldFive are zero-knowledge, the server only ever holds ciphertext, so neither can train a model on your files or scan their contents in the first place. This is a shared property of the two architectures, not a point of separation. We list it because it is a frequent question.
Pricing. ShieldFive's free tier is 20 GB with no card required. Shield+ is 2 TB at €2.75/month billed every three years, €6.67/month billed annually, or €7.99 billed monthly. Internxt publishes its own plans; compare them directly on current terms, since both vendors change pricing over time.
Where Internxt is ahead, honestly
A fair comparison has to run both ways, and with a competitor this close, it especially has to. Here is where Internxt is the stronger choice today.
A completed independent assessment. This is the big one. Internxt has had its applications and cloud services penetration-tested by Securitum, a European security firm, and it holds an independently verified ISO/IEC 27001:2022 certification. ShieldFive's crypto core is open and readable, but it has not yet completed an external audit or any comparable certification — that work is planned, not done. If a completed, independent assessment is a hard requirement right now, Internxt is ahead, and it would be dishonest to imply otherwise.
Track record. Internxt has shipped this product, with this architecture, for longer than ShieldFive has existed. Maturity is real, and Internxt has more of it.
Copyleft licensing. Internxt's clients are largely AGPL-3.0, a strong copyleft licence that obliges downstream modifications to stay open. ShieldFive's crypto core is Apache-2.0, which is more permissive. Neither is "better" in the abstract, but if you specifically want copyleft, Internxt's choice fits that preference.
If you want an EU-hosted, open-source, zero-knowledge product that has already been independently tested, Internxt is a strong and honest pick.
Which one fits you
Internxt fits you if you want an EU-based, open-source, zero-knowledge storage product that has already been independently tested and certified, and ML-KEM-512-level post-quantum protection meets your requirements — its free tier is 1 GB.
ShieldFive fits you if you want the same EU, open-source, zero-knowledge foundation but with the highest standardized post-quantum margin (ML-KEM-1024) as the default on every upload, and a larger 20 GB free tier — with the honest caveat that ShieldFive's external audit is still ahead of it, not behind it.
Try it
The way to evaluate this is in practice. ShieldFive's free tier is 20 GB with no card, enough to test the workflow with non-critical files first — upload, share with expiry, revoke — before moving anything that matters. Migration is a risk-tiering decision: move the highest-sensitivity files first, the ones where the larger post-quantum margin actually changes the exposure, and leave the rest wherever it already works.
This comparison reflects each vendor's public documentation as of 2026-06-17 and will be updated as the products change.